Weather manipulation in Paris to win $20,000 on Polymarket?
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25 Apr 2026 •
Reading time: 2 minutes
In early April, unusual temperature readings recorded near Charles de Gaulle Airport in Paris attracted attention. Two sudden and brief rises in temperature, difficult to explain by natural causes, coincided with bets placed on Polymarket.
A puzzling weather anomaly
In early April, on the outskirts of Paris, an unusual phenomenon caught the attention of weather observers. Near Charles-de-Gaulle Airport, a weather station recorded a temperature of around 18°C in the late afternoon, then at around 6.30 pm, the thermometer shot up by more than four degrees, reaching 22.5°C, before dropping almost immediately.
At this stage, experts considered natural causes. Direct exposure to the sun, for example, could have skewed the readings. But this hypothesis was soon called into question, as less than two weeks later, a second episode occurred. This time, around 9 pm, when it was already dark, the measured temperature rose from around 16 °C to nearly 21.9 °C in half an hour, before returning to its initial level around 10 pm.
Other possibilities then emerged: a technical fault, a maintenance issue, or even a one-off malfunction of the equipment.
The shadow of online betting
In parallel with these events, on the Polymarket prediction platform, users placed bets… on the temperature recorded at this Parisian weather station. The dates and times match. On 6 April, around 6.30 pm, and on 15 April, around 9.30 pm — exactly at the time of the observed temperature rises.
According to available information, these bets are said to have generated significant winnings. On 6 April, one bettor is reported to have won around $14,000. A few days later, on 15 April, another bet is said to have netted nearly $20,000. If the results were manipulated, this would mean that certain parties may have deliberately altered the actual conditions to guarantee their winnings.
This is where a theory as surprising as it is plausible comes into play. According to some speculation, the temperature readings may have been manipulated locally by directly heating the weather station’s sensor with a hairdryer. This hypothesis remains to be confirmed, but it illustrates the level of suspicion surrounding the case.
An investigation has been referred to the police to determine the exact cause of these temperature variations.
Prediction markets under scrutiny
At the heart of this case lies Polymarket, a betting platform based on real-world events. Users can place bets on future outcomes, whether in politics, the economy or the weather.
However, in France and Belgium, this type of service is illegal. Prediction markets are not permitted to operate in these countries.